Vaccines are one of the chief strategies employed to prevent human disease. Currently over two dozen vaccines are available to combat diseases caused by viral (e.g., chickenpox, hepatitis B, measles, polio) and bacterial contagions (e.g., cholera, tetanus, typhoid, diphtheria). Similarly, vaccines are used to prevent a host of afflictions in domesticated animals including but not limited to poultry, horses, pigs, and other animals.
While several vaccines (including influenza vaccines) are still produced in fertilized chicken eggs (Gallus gallus domesticus), the greater number of vaccines are produced in cell culture. In one instance, well characterized cell lines (e.g., Vero Cells) are first infected with live or live-attenuated viruses. Subsequently, the supernatant containing progeny viral particles is collected and processed to create highly immunogenic doses of vaccine that can then be distributed amongst the population.
Despite the demonstrated success of vaccines, the ability to eradicate or manage disease outbreaks is repeatedly challenged by the costs and manufacturing limitations of vaccine production. This is best illustrated with polio vaccines. Poliovirus is a human enterovirus and the causative agent of poliomyelitis, an acute paralysis resulting from fecal-oral transmission of this neuro-degenerative agent. At this time, vaccines have been created to limit the spread of polio, and include the high effective (and significantly more expensive) inactivated polio vaccine (IPV), the less efficacious (and more economical) oral polio vaccine (OPV). For technical reasons related to the reversion of attenuated OPV virus particles to highly infectious neurovirulent poliovirus, successful eradication of polio will be aided by the development of new technologies that significantly decrease IPV manufacturing costs.